Light protective wrapper



Patented Oct. 27,. 1936 PATENT OFFICE LIGHT PROTECTIVE WRAPPER Dudley H.Grant, Berkeley Heights, N. J., assignor to Stanco Inc., a corporationofDelaware No Drawing.

Application February 2, 1931, Serial No. 513,058

. 2 Claims. (01. 91-68) This invention relates to light protectivewrappers and the process of making the same and will be fully understoodfrom the following description.

I have discovered that wrappers of paper, cloth, transparent films ofcellulose or hydroxycellulose (made by precipitation from viscose,cuprammonium or other cellulose solutions), gelatine, acetylcellulose,nitrocellulose, pyroxylin or other thin flexible material, such as areused to wrap commodities which may be injuriously affected by sunlight.or other actinic light, may be rendered wholly or partially imperviousto such light by means of substantially colorless substances having theproperty of absorbing light waves of short wave length.

The following substances may, for example, be used in the preparation oflight protective wrappers according to the present invention: quinineand its salts, aesculin, methyl esters of naphthalene carboxylic acids,salts of naphthol sulfonic acids, phthalic acid salts, and in. generalprotective substance to the solvent used in the manufacture of thepyroxylin material. Such or similar methods may be used with other thin40 flexible materials to incorporate the light protective ingredient.Laminated sheets of two or more layers of the same or difierentmaterials,

one or more layers containing the protective substance, may also beused.

. The amount of the ingredient added depends on the substance and alsoon the degree of light protection desired and correspondingly may bevaried within large limits.

The following examples will serve to illustrate 60 my process and themethod of carrying it out.

Example 1 Sheets of paper, preferably the translucent paper known in thetrade as glassine, are coated on one 'or both sides with a lacquercomposed 5 approximately as follows:

Per cent FYIOXylin 3 Amyl acetate or other medium boiling solvent. 5-2510 Aesculin 0.5-5 Monoethyl ether of ethylene glycol or other blendingagent 3-10 Ethyl acetate, acetone or other low boiling solvent 10-30 15Castor oil or other plasticizer 2- 5 Benzol, toluol, naphtha or otherdiluent 30-70 For aesculin in the above example may be substitutedquinine alkaloid, quinine ricinoleate, linoleate or other quinine saltcompatible with the lacquer film, phenanthrene, anthracene, or othersubstances of the types specified above.

Example 2 In the manufacture of thin sheets of cellulose orhvdroxycellulose by regeneration (coagula-' tion) from solutions ofviscose, some of the lightprotective materials specified above may beincorporated with the viscose solution before 00- 'agulation. Among suchsubstances may be mentioned the sodium salts of carboxylic or sulfonicacids derived from naphthalene, anthracene; phenanthrene, fiuorene andother conjugated hydrocarbons. '35

The transparent sheets of regenerated cellulose or hydroxycellulose,after washing and drying, may also be coated with lacquers as describedin Example 1.

Example 3 V 40 1% to 20%. The sizing solution is then applied to paperor cloth.

Example 5 Transparent films, wrappers, caps, capsules, etc., made ofgelatine, gelatine-glycerine, formaldehyde-gelatine or chromatedgelatine have water-soluble protective substances such as quininebisuli'ate, sodium naphthalene sulfonates or other salts of sulfonic orcarboxylic acids of conjugated hydrocarbons, added to the gelatinesolution in amounts of 1% to 30% before drying coagulating or exposingto light.

Example 6 Example 7 To paper pulp in the heater is added a solutioncapable of furnishing a water-insoluble lightprotective substance of theclasses mentioned above, when such solution is decomposed by subsequentaddition of another reagent such as acid or alkali, and the protectivesubstance is thereupon precipitated in intimate contact with the paperfiber, remaining in the finished paper. For example, to 1,000 lbs. ofpaper stock inthe pulp state in the beater is added '10 lbs. of quininehydrochloride dissolved in water. To the mixture is then added an amountof sodium resinate, stearate, etc., equivalent to the quinine salt or inslight excess, thereby precipitating quinine resinate, stearate, etc.,in the pulp. For sodium resinate or stearate may be substituted anyalkali salt of an acid of which the quinine salt is insoluble in water.

Similarly, water-insoluble protective substances of acid nature, such asnaphthalene carboxylic acids, may be precipitated in the pulp by addingtheir alkali salts to the pulp and then acidifying it with hydrochloricor other acid. In this case. I find it advantageous to combine thesodium salts of naphthalene carboxylic acids (or carboxylic acids ofother conjugated hydrocarbons) with sodium resinate. Subsequentacidification then precipitates the carboxylic acids mixed with rosinacids, which aid in their fixation in the paper fiber. For example, 15lbs. of sodium naphthalene beta-carboxylate and 20 lbs. of sodiumresinate are dissolved in water containing 1,000 lbs. of paper stock inthe beater. After thorough mixing, 2 gallons, or a suitable slightexcess, of hydrochloric acid is gradually added. In either case, whenthe pulp passes to the paper machine, it retains the light-protectivesubstance intimatelymixed with the fiber, and remaining in the finishedpaper.

Having thus described my invention and the method of carrying it outwhat I claim is:

1. A thin, flexible transparent wrapper of regenerated cellulose, forarticles tending to deteriorate if subjected to actinic light, saidwrapper comprising a colorless substance adapted to prevent the passageof objectionable amounts of such light, in which the colorless substanceis a coating having the following approximate composition:

Per cent Pyroxylin 3 Amyl acetate or other medium boiling solvent 5-25Colorless absorber of actinic light 0.5- 5 Monoethyl ether of ethyleneglycol or other blending agent Ethyl acetate, acetone or other lowboiling solvent 10-30 Castor oil or other plasticizer. 2- 5 Benzol,toluol, naphtha or other diluent 30-70 2. A wrapper according to claim 1in which the colorless absorber of actinic light is aesculin.

DUDLEY H. GRANT.

